How to get list in single column in a query

Question

Hello.
I wonder if there is a way of getting with one query (no pl/sql code) a whole list of columns with a separator between them.
I know I can get that without the separators with a cursor expression:
SQL> with test_table as (
  2  select 1 col1, 'a' col2 from dual
  3  union
  4  select 1 col1, 'b' col2 from dual
  5  union
  6  select 1 col1, 'c' col2 from dual
  7  union
  8  select 2 col1, 'a' col2 from dual
  9  union
10  select 2 col1, 'c' col2 from dual
11  union
12  select 2 col1, 'd' col2 from dual
13  union
14  select 2 col1, 'z' col2 from dual
15  )
16  select col1, cursor (select b.col2 from test_table b where b.col1 = a.col1 order by b.col2) col2_list from test_table a
17  group by col1
18  /
      COL1 COL2_LIST
         1 CURSOR STATEMENT : 2
CURSOR STATEMENT : 2
C
a
b
c
         2 CURSOR STATEMENT : 2
CURSOR STATEMENT : 2
C
a
c
d
zBut the output that I want is (using the separator ';'):
      COL1 COL2_LIST
         1 a;b;c
         2 a;c;d;zI do not know how to handle a cursor expression without using a pl/sql block of function. Can it be done using analytic functions?
Thanks in advance.

Answer 1

Like this...
SQL> ed
Wrote file afiedt.buf
  1  with test_table as (
  2    select 1 col1, 'a' col2 from dual union
  3    select 1 col1, 'b' col2 from dual union
  4    select 1 col1, 'c' col2 from dual union
  5    select 2 col1, 'a' col2 from dual union
  6    select 2 col1, 'c' col2 from dual union
  7    select 2 col1, 'd' col2 from dual union
  8    select 2 col1, 'z' col2 from dual)
  9  --
10  select col1, ltrim(sys_connect_by_path(col2,','),',') as col2
11  from
12    (select col1, col2, row_number() over (partition by col1 order by col2) rn
13    from test_table)
14  where connect_by_isleaf = 1
15  connect by col1 = prior col1
16  and rn = prior rn+1
17* start with rn = 1
SQL> /
      COL1 COL2
         1 a,b,c
         2 a,c,d,z
SQL>